A coupling device comprises a tubular body having a first connection section and a second connection section for co-operating respectively with a first duct and with a second duct. The first connection section is arranged to be engaged by force in one end of the first duct, and the second connection section is arranged, for example, to receive one end of the second duct and to retain it, e.g. by means of a radial latch or a clamp.
Such coupling devices need to be capable of withstanding numerous stresses, in particular when they are fitted to motor vehicles, which constitute surroundings that are very demanding.
Thus, coupling devices are highly stressed mechanically and they need to be capable in particular of withstanding the pressure of the fluid in the circuit, forces exerted by the pipe end and by the tubular element, vibration that results from operation of the vehicle, impacts, in particular in the event of/a vehicle accident, . . . . These stresses are in addition to the large variations in temperature that exist between winter low temperatures and high temperatures in the vicinity of an engine that is running.
Couplings must also present low permeability to the fluids they convey and must withstand them chemically as well as the fluids with which they might into contact in the vehicle.
Coupling devices must also be reliable, easy to make, and inexpensive.
The structure of coupling devices is thus the result of making a compromise in satisfying those requirements.
The tubular body is thus generally molded as a single piece of plastics material, thereby making it possible to obtain coupling devices that are lighter in weight than metal coupling devices, and inexpensive providing they are simple in shape. The use of a body that is made entirely out of plastics material can however be penalizing concerning the mechanical strength of the coupling device and also the permeability of the coupling device to the fluid it conveys, unless use is made of a plastics material that is very elaborate and therefore expensive, or unless the wall of the tubular body is thickened, thereby nevertheless increasing its weight and bulk.
In order to improve the anchoring of the first connection section in the first duct, it is known to fit a metal anchor member thereto. The anchor member may be merely a toothed washer received in a groove of the tubular body. Mounting the anchor member in that way requires the body to be made in two portions that are generally snap-fastened together, thereby increasing the cost of fabricating the tubular body. The anchor member is then free to rotate relative to the body, which can therefore pivot relative to the first duct, and that can be troublesome in certain applications. Fastening the anchor member to the body is generally difficult and in certain configurations there is a risk of the anchor member becoming lost prior to the coupling device being mounted in the first duct. To solve this problem, it is possible to overmold the tubular body onto the anchor member. Nevertheless that increases the cost of fabricating the tubular body.